Description of a new goatfish species , Upeneus randalli n . sp . ( Mullidae ) , from the Persian Gulf , with remarks and identification keys for the genus Upeneus

The number of species of the goatfish genus Upeneus from the western Indian Ocean has increased considerably due to recent taxonomic efforts. Here we describe a new species, Upeneus randalli n. sp., based on body and fin coloration and 50 morphometric and meristic characters of eight specimens from the Persian Gulf, and supported by comparative data from a taxonomic review of western Indian Ocean Upeneus species and additional material from collections. Upeneus randalli is distinguished from congeners by the combination of 8 dorsal-fin spines, 14 pectoral-fin rays, 23 to 25 gill rakers, 28 to 30 lateral-line scales, pectoral-fin width 22 to 26 times in SL, and red bars on both caudal-fin lobes. We provide two identification keys: one key is for distinguishing among four species groups and the morphologically unique U. filifer, accounting for all 28 species of the genus, and the other key is for the six closely related species of the “U. tragula group” from the western Indian Ocean, including U. randalli n. sp. Since the colour patterns fade away soon after collection and can be completely lost during preservation, morphometric and meristic characters are important for correctly identifying U. randalli n. sp. and the closely related U. margarethae. The latter species shows considerable variation in body form in different areas of the western Indian Ocean. We discuss the significance of detailed comparative studies of caudal-fin colour patterns and body-form characters for obtaining a deeper understanding of interand intraspecific diversity among Upeneus.


INTRODUCTION
The number of known goatfish species (Mullidae) has dramatically increased due to recent taxonomic efforts that have targeted the coastal fish diversity of the western Indian Ocean (Randall and Heemstra, 2009;Randall and King, 2009;Uiblein and Heemstra, 2010;Uiblein and Heemstra 2011).For instance, in a review of the genus Upeneus from this area a total of 16 species were reported (Uiblein and Heemstra, 2010), which represents an increase in the number of species of over 40% compared to an earlier account by Kumaran and Randall (1984), who only listed nine species.
The widest ranging species among the four new Upeneus species described in the review (Uiblein and Heemstra, 2010), U. margarethae, has been reported to occur along the East African coast and Madagascar, in the Red Sea, the Persian Gulf, off Sri Lanka, off NW Australia, and in the Arafura Sea (W-Pacific).Since no documentation of fresh colour was available from other areas and comparisons indicated geographic variation in body form, Uiblein and Heemstra (2010) recognized the main distribution area of this species to be between Mozambique, Somalia and Madagascar, where morphological variation appeared to be rather low among the localities from which the type specimens originated.
Shortly after publication of the review, additional specimens of Upeneus from the Persian Gulf were found at the Bishop Museum, Hawaii.Among this material were seven specimens of a small Upeneus species with eight dorsal spines, which appeared to be closely related to the single specimen of U. margarethae from the Persian Gulf that had been included in the review.However, examination of colour photographs of two specimens from the Bishop Museum collection suggested that they were significantly different to U. margarethae, and therefore detailed taxonomic studies would be necessary.
Here we report the results of the examination of 50 morphometric and meristic characters and the colour patterns of the eight Persian Gulf specimens.A new species, Upeneus randalli n. sp., is described and compared with closely related species from the western Indian Ocean using published data and new results obtained from three Bishop Museum specimens of U. margarethae originating from Mafia Island, Tanzania, and Kerala, SW India.An updated diagnosis for U. margarethae is provided to account for changes in several morphometric and meristic characters due to the exclusion/inclusion of study material and to facilitate direct comparison with the closely related U. randalli n. sp.
We provide two identification keys based on published data of 25 additional species (Uiblein and Heemstra 2010;Uiblein and Heemstra 2011) and new data gathered from 6 Pacific U. filifer (Ogilby, 1910) during a visit to the Australian Museum: a key for distinguishing among four species groups of Upeneus and the morphologically unique U. filifer, and a key for the "U.tragula group" from the western Indian Ocean, which consists of U. randalli n. sp. and five other closely related species.In addition, we further examine the morphological variation among western Indian Ocean U. margarethae populations.

MATERIALS AND METHODS
Abbreviations and descriptions of 50 characters are provided in Table 1.The data of 252 specimens of 24 Upeneus species published in the review by Uiblein and Heemstra (2010) were used for preparing the keys and species comparisons.Additional material for U. filifer and U. margarethae that was examined for this study is listed below.Data from Uiblein and Heemstra (2011) were also included.
For the intraspecific comparison among Upeneus margarethae, Principal Component Analysis (PCA) with size-adjustment based on the residuals obtained from log-log regressions of the morphometric variables with standard length, was used to obtain information on optimal distinction (Uiblein and Winkler, 1994).
Distribution.In all major oceans, tropical to subtropical, only a single species in the Atlantic and two in the Mediterranean, both so-called "Lessepsian" immigrants from the Red Sea after the opening of the Suez Canal (Ben Tuvia 1966).
A single species, U. xanthogrammus Gilbert, 1892, has been described from the east Pacific; however, no material was available for our taxonomic studies.There have been many misidentifications in this genus and the validity status of this species is still unclear to us.

Key to Upeneus species groups
In Upeneus one single species and four species groups can be distinguished from each other based on a small set of characters that includes the number of dorsal spines and gill rakers, the length of the longest dorsal-fin spine, the length of pelvic and pectoral fins, and the presence or absence of caudal-fin bars and mid-lateral body stripes (Uiblein and Hemstra, 2010;Uiblein and Heemstra, 2011) Diagnosis.Dorsal fins VIII+9; pectoral-fin rays 14; gill rakers 6-7+17-19=23-25; lateral-line scales 28-30; measurements in % SL: body depth at first dorsal-fin origin 23-24; body depth at anus 19-22; caudal-peduncle depth 9.9-11; caudal-peduncle width 2.9-3.8;maximum head depth 19-21; head depth through eye 15-16; head length 27-30; orbit length 6.2-7.4;upper jaw length 10-11; barbel length 16-20; caudal-fin length 27-30; anal-fin base 9.4-11; anal-fin height 15-19; pelvic-fin length 20-22; pectoral-fin length 20-22; pectoral-fin width 3.8-4.4;first dorsal-fin height 19-22; second dorsal-fin height 16-20; total bars on caudal fin 11-13, with 5 red bars on upper caudal-fin lobe, 4 on lobe itself and one at lobe base; 6-8 red bars on lower caudal-fin lobe; caudal-fin bars not retained on preserved fish, apart from some traces of bars mostly on lower lobe and dark pigmentation at lower lobe tip; 3 horizontal series of black dots mid-laterally, 3-4 dots below posterior part of first dorsal-fin base, 2 below anterior part of second dorsal-fin base, and 2 behind second dorsal-fin base, dots not retained in preserved material; first dorsal fin pale with some reddish pigment anteriorly and dorsally; second dorsal fin, pelvic and anal fins with reddish stripes; fin colour not retained in preserved fish; barbels white; body and head reddish marbled; ventral side of head and belly white; body uniformly pale brown in preserved fish, sometimes darker dorsally, with vague brown band mid-laterally.
Fresh colour (Fig. 1).Head and body white laterally, with some irregular red markings forming marblelike pattern; ventral part of head and belly white; tip of snout and upper jaw beige; iris red; weakly indicated mid-lateral beige stripe from eye to caudal-fin base running anteriorly below lateral line and posteriorly along or slightly above lateral line; stripe overlain by 3 horizontal series of black dots mid-laterally, 4 dots below rear part of first dorsal-fin base, 2 below anterior part of second dorsal-fin base, and 2 behind second dorsal fin base; the latter associated with dark pigmentation dorsally, forming saddle immediately behind second dorsal fin; dorsal fins pale, the first with some red markings anteriorly and dorsally, the second with one or 2 sub-horizontal red stripes; pectoral fins hyaline; pelvic and anal fins pale, pectoral fins with 4 dusky-red stripes; anal fin with 2 dusky stripes; caudalfin upper lobe hyaline, with 4 red bars on lobe itself (one at lobe tip) and 5 th faint bar at the base of lobe; bar width less than width of pale interspaces between bars; lower lobe pale-reddish with 7 dark red bars, one bar at tip; bar width similar to width of pale interspaces (in the photographed paratype (Fig. 1), this pattern is less evident, as bars seem to be connected with each other, but see also Remarks section); barbels white.Preserved colour.Head and body pale beige to pale brown; body of holotype becoming darker dorsally, with broad brown mid-lateral band from behind operculum to caudal-fin base; head and operculum of holotype with whitish patches; holotype and several paratypes show dark saddle behind second dorsal fin that reaches to lateral line; all fins transparent and without pigment, except for some remains of bars on caudal fin including dark pigmentation on tip of lower caudal-fin lobe of holotype and a few paratypes; holotype shows no bars on upper caudal-fin lobe and remains of 6 distal-most bars on lower caudal-fin lobe, with dark pigmentation retained on inner dorsal half of lower lobe and on tip; lateral line distinct, extending to or slightly beyond caudal-fin base.
Etymology.The name of this species "randalli" is in honour of the esteemed ichthyologist John E. "Jack" Randall who collected six of the seven paratypes, transferred the holotype to the Bishop Museum collection and took a photograph of the fresh holotype used for the colour description.
The photographed paratype deviates considerably in body and fin colour from the holotype (see Fig. 1).This colour difference may (at least partly) derive from different post mortem treatment.Dead goatfishes with a pale body colour frequently turn red if exposed to air for a longer period of time.The tail pigmentation in red-barred goatfishes may also fade quickly after death.Upeneus randalli attains 11 cm SL; depth 20 m.Uiblein and Heemstra, 2010 (Fig. 1-3, Table 2)
Distribution.Mozambique to Somalia, Madagascar, Red Sea, SW India, Sri Lanka, NW Australia, N Australia (Arafura Sea).
Remarks.Table 2 shows the morphometric and meristic data of the currently known 28 specimens of U. margarethae from the western Indian Ocean.The exclusion of the formerly misidentified specimen of U. randalli and inclusion of three additional specimens from Mafia Island and Sri Lanka affected the ranges of seven morphometric and two meristic characters, four of them being diagnostically important (Table 2).
No photographs of fresh fish are available for Upeneus margarethae from areas other than Mozambique and due to indications of morphological variation among geographically well-separated populations, Uiblein and Heemstra (2010) restricted the selection of type specimens to the East African coast and Madagascar.
The second and third principal components of the PCA conducted in the current study allowed us to separate U. margarethae from the SW Indian Ocean, the Red Sea, and S-India/Sri Lanka (Fig. 3) Accordingly, the four specimens from SW India and Sri Lanka differ in a combination of several characters, including eye size, length of anal-fin base, second dorsal fin height, maximum head depth and interdorsal distance from nearly all others; and the two Red Sea specimens dif-fer in the combination of jaw length, barbel length and barbel width from the others.However, the percentage of total variance explained by the second and third principal components is relatively low (14 and 9% respectively).
Larger data sets with more specimens would be required to examine these distinctions more broadly and to better contrast morphological variation within populations with differences among populations at various geographical scales (Uiblein and Winkler, 1994).

DISCUSSION
This study provides further evidence of the high diversity among goatfishes of the western Indian Ocean region.The discovery of another species of the genus Upeneus in the Persian Gulf, in addition to U. oligospilus (cf.Uiblein and Heemstra, 2010), indicates that this area has been insufficiently studied and may be biogeographically distinct (see also Ghanbarifardi and Malek, 2009).Due to the lack of data from adjacent areas and the complex geological history of this part of the Western Indian Ocean (e.g.Santini and Winterbottom, 2002), it remains unclear to us whether U. oligospilus and U. randalli should be considered as strictly endemic to the Persian Gulf.
The co-occurring Upeneus randalli n. sp. and U. oligospilus differ from each other and from their close relatives, U. margarethae and U. tragula, in their caudal-fin colour patterns, including the number and form of bars on the caudal-fin lobes.Conspicuous, contrasting colour patterns may have certain functions related to predator avoidance and/or social communication.For instance, Uiblein and Nielsen (2005) found support for both functions when they studied the formation of contrasting eye-spots or ocelli on the dorsal fins of the ophidiid genus Neobythites and related this evidence to the high diversity found in this genus, which has over 50 currently known species.
The genus Upeneus is characterized by a highly modifiable body form that allows colour-independent distinction among species and populations, as reported in a comparative morphological study of the three goatfish species U. sulphureus, U. sundaicus, and U. tragula from Hainan Island, South China Sea (Uiblein et al., 1998).Since coloration fades away after death and may be completely lost during preservation, a thorough analysis of body form characters greatly facilitates identifying collected material, and also provides information on functional relationships between co-occurring populations of different species and habitat use as well as small-scale geographic differentiation patterns (Uiblein et al., 1998).Our multivariate analysis of geographical variation in morphometric characters of U. margarethae substantiates these earlier findings.Apart from differences among geographically well separated areas, more closely connected populations like those from the SW-Indian Ocean (Fig. 3) may also differ from each other considerably and hence deserve to be studied in detail in terms of micro-geographic phenotypic and genetic differentiation.

Fig. 2 .
Fig. 2. -Pectoral-fin width against gill-raker number (on top), head depth through eye against caudal-peduncle width (below), and orbit length against SL (on bottom) in Upeneus randalli n. sp.from the Persian Gulf and U. margarethae from the western Indian Ocean.

Fig. 3 .
Fig. 3. -Scores of the second and third axis of Principal Component Analysis based on 40 morphometric characters in 28 Upeneus margarethae from different areas in the western Indian Ocean, with trends for the highest contributing characters indicated by arrows.

Table 1 .
-Abbreviation and description of morphometric and meristic characters

Table 2 .
Uiblein and Heemstra (2010) counts for Upeneus randalli n. sp. and U. margarethae of the Western Indian Ocean.Characters showing deviations fromUiblein and Heemstra (2010)are indicated in bold.